Emitter switching is a circuit configuration in which a low-voltage power transistor (typically an MOS transistor) cuts off the emitter current of a high-voltage power transistor (typically a bipolar transistor) in order to switch it off. This configuration, which up until now was obtained by means of discrete components, offers the following advantages:
it increases the strength of bipolar transistor as far as the possibility of inverted secondary ruptures (ESB) occurring are concerned;
it combines the current and voltage carrying capacity of a piloted transistor and the high speed of a low-voltage transistor;
it enables the system to be piloted directly with linear logic circuits, through the MOS gate.